1. Field
Embodiments relate to a semiconductor memory device. More particularly, embodiments relate to a phase change memory device and a write method thereof.
2. Description of the Related Art
A memory semiconductor device is classified into a volatile semiconductor memory device and a non-volatile semiconductor memory device based on whether or not power supply is required to maintain stored information.
A volatile memory device, e.g., a dynamic random access memory (DRAM), a static random access memory (SRAM), etc., has a fast operating speed but needs to be supplied with a power source to maintain stored information. A non-volatile memory device, e.g., a read only memory (ROM), a flash memory, etc., does not have the above-mentioned power supply limitation but has a slow programming speed. Accordingly, a new kind of a memory device is on demand for overcoming various limitations of a currently used memory device.
In view of miniaturization/portability trends of electronic products and prices of semiconductor products, a new kind of a memory device needs to be developed in order to satisfy a variety of technical requirements, including non-volatility, low power consumption, fast operating speed, and high integration. Next generation memory device potentially satisfying the above technical requirements include a phase change memory (PRAM) device, a magnetic random access memory (MRAM) device, and a ferroelectric random access memory (FeRAM) device. In particular, the PRAM device does not have technical difficulties that may occur during a formation of a phase change alloy thin film. Thus, the PRAM device can be manufactured at a lower cost. Additionally, the PRAM device has prolonged product durability, as information stored therein may be modified more than about 1013 times, and a fast operating speed.